Spark plug



0. SPAHH.

SPARK PLUG.

APPLlcATioN FILED MAR.13. 1920.

Patented Oct. 17, 1922.

UNITED STATESV lnaiuslar OFFICE.

SPARK PLUG.

Appliotion ile'd latch 13, 1920. Serial No. 365,375.

The internal combustion engine is ren-A dered more or less ineilicient because of the ractical impossibility of completely exliausting all of thev burnt gases after the power stroke has taken place. The bulk of the burnt gas, which remains in the cylinder, collects i'n the end of the spark plug, mixes with the fresh gas, and renders the charge less readily burnable at the point where the spark, intended to ignite the gas, occuis.

This results in a slow ignition and decreased eiliciency.

In accordance with my invention, I provide a spark plug, which is so constructed as to permit of an inflow of fresh air through the plug and into the cylinder, durinv the intake stroke of the motor, which wi l clear out any burnt gas remaining in the end of the plug` and about the electrodes and which will tend to neutralize the burnt gas remaining inthe cylinder. The introduction of a limited amount of fresh air to the cylinder through the lug has also the result of preventing the ormation of carbon in the plug and tends to homogenize the incoming mixture of fresh gas, which, upon reaching the cylinder, has tended to disintegrate to some extent.

The introduction of the air tends to keep the spark plug cool and prevents the heat from breakin vthe exposed end of the porcelain insu ators and burning the electrode.

Gasoline may be introduced through the plug into the cylinder, for priming, and for washing or cleaning same without removing Vthe lug from engin e T e spark plug embodying my invention is so constructed as to readily admit air during the intake stroke of the engine, -but to positively prevent the escape of gas from the cylinder duringthe compression, power or exhaust strokes.

I Will-now proceed to describe a preferred embodiment of my invention with reference to the accompanying drawings, in which-- Figure l is a perspective v1ew of a spark plig embodying my invention.

lgure 2 is a sectional view through the centre of the spark plug shown in Figurel.

The body a ofthe lug is externally threaded at its lower end) for insertion into an engine and internally threaded at its -upper end for the reception of the packing nut b. The porcelain insulator e extends into the body of the plug and is provided with a flange d which rests on a shoulder e in the interior'of the plug body. The insulator is retained'in positlon by the packing nut b, which is tightened down against a Washer f to make a tight joint.

A hollow binding post g extends through the centre of the `insulator and is retained therein by nuts h and i, one at either end. Passages j are formed in the porcelain, and extend transversely to the binding post and in connection therewith. The passages extend preferably from a point just beneath the shoulder e and communicate with the rear end of the annular space between the body a and the insulator c.

An electrode k is secured in the lower end of the binding post and forms a spark gap with a second electrode Z secured in the lower end of the body a.

A cylindrical casing m, having a cent1-al passage fn, countersunk at the upper end as at o is threaded to the upper end of the binding post. A disk valve p having cut out edges is adapted' to rest in the bottom of the countersink which is tapered as shown in Figure 2. A valve seat g, having a central bore r, is threaded into the countersink and adjustable toward valve p. A lock nut s holds the valve seat 1- in its adjusted position.

In operation on the intake stroke of t-he engine,l the valve p rests in the bottom of the countersink o and air is drawn through its cut out edges down through the hollow binding post g and into the end of the plug body, from which it clears out all the burnt gas and pain to the cylinder mixes with the incoming sh charge.

VThe valve seat g ma be adjusted toward the valve p so that t e clearance. between them is just suicient to admit the desired quantity of air. When' the engine is on the compression, power and exhaust strokes,

the pressure in the cylinder extends lup through the hollow end of the plug body into the hollow binding post and acts on the lower side of the valve p', raising` it against seat g and preventin the vescape of gas through the plug. 'l that on the intake stroke the valve is drawn away from seat g and air enters the plug, under the inuence of the suction of the engine, while at all other times during the cycles of loperation of the engine, the pressure in the cylinder acts on valve p to raise it and maintain it on'its seat reventing the escape of gas lfrom the cylin er.

Should it be desirable to prime the engine, gasoline may be injected into the top of the valve seat and will low past the valve, through the centre of the plug and into the cylinder.

It will be observed that there are no dead spaces communicating with the open front end of the lug, into which burnt gas can flow and co ect. 0n the contrary, the pas` sages jcommunicate with the annular space between the body as and the insulator c at-- the rear of said space, thus insuring that the rst inflowing air will clear out all the burnt gas and that there will mix with the incoming charge no burnt gas but only fresh air that inflows after the burnt gas has been cleared out.

By incliningV the passages j at an acute angle to the axis of the plug, the distance through which a spark might jump from the metal binding spost to the metal body will be increased, thus eliminating the possibility of any spark forming except between the electrodes proper. l

Having now fully described my invention, what I claim and desireto protect by Letters Patent is:-

1. A spark plug for internal combustion engines comprising a hollow body, an insulator extending into said body and shaped us it will be seenl lator extending into said body and shaped to alord. an annular recess, closed at its rear, between the insulator and the body, a hollow binding post extending through sai-*l insulator, vand an electrode secured to the front of the binding post, there being a i passage communicating with the hollow interior of the binding post and extending through the wall of the binding post and the body of the insulator into the rear end of the annular recess between the insulator vand the body.

3. A spark plug having an air channel extending therethrough and enlarged at its rear end, the lower end of the enlarged portion having tapering walls, a disc valve, hav- .ing indentations on its peri hery, horizontally disposed within the e arged rear end of the air charmel, and a channeled valve seat extending within the enlarged rear end ofthe air channel, said valve being movable downwardly to allow flow of air into the plug `and upwardly against the seat to ob struct outflow of gases in the reverse direction the ,extent to which the valve recedes from its seat during iniow of air.

Y In testimony of which invention, I have hereunto set my hand, at Philadelphia, on this 12th day of March, 1920.

OTTO SPAHR.

Ilpost and extending through the wall ol' said valve seat being adjustable to vary 

